Let's build it with the factory map then.

indra/newview/llfloatermarketplacelistings.cpp

@@ -358,7 +358,8 @@ LLFloaterMarketplaceListings::LLFloaterMarketplaceListings(const LLSD& key)
 , mPanelListingsSet(false)
 {
 	//buildFromFile("floater_marketplace_listings.xml");
-	LLUICtrlFactory::instance().buildFloater(this, "floater_marketplace_listings.xml");
+	mFactoryMap["panel_marketplace_listing"] = LLCallbackMap([&](void*) { return mPanelListings = new LLPanelMarketplaceListings; });
+	LLUICtrlFactory::instance().buildFloater(this, "floater_marketplace_listings.xml", &getFactoryMap());
 }
 
 LLFloaterMarketplaceListings::~LLFloaterMarketplaceListings()
@@ -384,8 +385,6 @@ BOOL LLFloaterMarketplaceListings::postBuild()
 	mInventoryText = mInventoryPlaceholder->getChild<LLTextBox>("marketplace_listings_inventory_placeholder_text");
 	mInventoryTitle = mInventoryPlaceholder->getChild<LLTextBox>("marketplace_listings_inventory_placeholder_title");
 
-	mPanelListings = static_cast<LLPanelMarketplaceListings*>(getChild<LLUICtrl>("panel_marketplace_listing"));
-
 	LLFocusableElement::setFocusReceivedCallback(boost::bind(&LLFloaterMarketplaceListings::onFocusReceived, this));
 
 	// Observe category creation to catch marketplace listings creation (moot if already existing)

indra/newview/skins/default/xui/en-us/floater_marketplace_listings.xml

@@ -67,7 +67,7 @@
       <panel
         name="panel_marketplace_listing"
         filename="panel_marketplace_listings.xml"
-        bottom="-5"
+        bottom="-435"
         follows="all"/>
       </panel>
     <panel

indra/newview/skins/default/xui/en-us/panel_marketplace_listings.xml

@@ -5,7 +5,6 @@
   follows="all"
   layout="topleft"
   width="308"
-  class="llpanelmarketplacelistings"
   height="440">
   <panel
     name="tool_panel"